Turkish President Recep Tayyip Erdogan declared victory in a contested referendum on constitutional changes that will significantly expand his powers.
Critics said the vote, which took place under a state of emergency imposed in the wake of last year's failed coup, was unfair and the opposition vowed to challenge the results. Here's a quick rundown on what happened in Sunday's vote and what lies ahead for Turkey.
The "yes" side won the referendum with 51.4 percent of the vote, compared to 48.6 percent for those opposed. Erdogan said turnout was estimated at 86 percent, which he described as proof of the strength of Turkish democracy.
WHAT IT MEANS
The 18 constitutional amendments mean Turkey's parliamentary system of governance is replaced with a presidential one. That allows the president to appoint ministers, senior government officials and hold sway over who sits in Turkey's highest judicial body, as well as to issue decrees and declare states of emergency.
Most of the changes won't take effect until after the next presidential and parliamentary elections, slated for Nov. 3, 2019. However, three amendments will automatically come into effect following the publication of official election results in 10 to 11 days, according to Mehmet Elitas, the deputy chairman of the governing party, AKP.
They include a repeal of military courts, a restructuring of Turkey's board of judges and prosecutors, as well as the annulment of a law that required the president to sever any party ties. AKP, the party Erdogan co-founded, said it would invite him to rejoin.
An unprecedented electoral board decision to accept ballots that didn't bear the official stamp has led to outrage among the opposition.
By law, for a vote to be considered valid, the ballot and the vote must bear official stamps. The system is designed to ensure only one vote is cast per registered voter and to avoid the possibility of ballot box stuffing.
Monitors of the Organization of Security and Cooperation in Europe said Monday the decision undermined important safeguards against fraud and was contrary to Turkish law. Opposition parties announced they would challenge the count.
Some European leaders reacted with concern over the result. German Chancellor Angela Merkel said the result shows "how deeply split the Turkish society is," while Austrian Foreign Minister Sebastian Kurz said the outcome was bound to complicate further cooperation between Ankara and the European Union.
Turkey's longstanding bid for EU membership was already in doubt and could be dropped for good if Erdogan follows through on suggestions to reintroduce the death penalty, which he reiterated after the referendum win.
The U.S. State Department on Monday "encouraged voters and parties on both sides to focus on working together for Turkey's future," while calling on the government to protect rights and freedoms "regardless of their vote on April 16."